Student Projects 2012

The CT river contributes about 70% of the total upstream load of most pollutants to
LIS. Many New England towns and cities have a long history of industrial activity
and legacy deposits of contaminants in upland watershed sediments continue to be a
strong source for LIS. During high river flows, water velocities are sufficient to
re-suspend sediment-associated contaminants and deposit them downstream in another
reach of the river. The recent CT river flows associated with tropical storm Irene
in August 2010 transported tremendous volumes of sediment to the mouth of the Connecticut
river. Fine-grain, metal rich sediment containing legacy pollutants are remobilized
during flood events and deposited preferentially in sheltered coves along river estuaries.
Research has shown that the marsh and cove sediments in the tidal areas of the Housatonic
river estuary are strongly enriched in Hg, Zn and Cu remobilized by floodwaters from
upstream deposits. As such, the chemical and physical characteristics of tidal cove
sediments in the lower CT river estuary will be a focus of this study. This study
will test the following hypotheses: (1) physical properties of the river channel and
cove sediments will vary from fine-grain, high organic matter content in the river
coves to coarser, low organic matter content in the river channels and outside the
mouth of the river in LIS; (2) metal contamination will be highest in fine-grained
high organic matter content sediment proximate to point sources of contamination;
and (3) metal contamination, particularly in the river coves, throughout the lower
CT river estuary will be greater than both their respective crustal abundances and
the extent of metal contamination in sediment sampled from LIS.

Water quality monitoring programs are an important aspect of determining the overall
health of ecosystems within Long Island Sound. Current monitoring programs within
LIS are conducted by interstate, state and local agencies, academic institutions,
and volunteer and community organizations. Government agencies and academic institutions
have primarily focused on the open sound while community and volunteer organizations
have examined water quality within rivers, bays and harbors. The Center for Coastal
and Marine Studies recently established a water quality monitoring station in New
Haven harbor at Long Wharf in January 2012. The monitoring program was established
in response to a lack of high quality monitoring data for New Haven harbor and to
provide a long-term continuous record of water quality measurements for the harbor.
The water quality data supplements our on-going sediment quality data collected during
the past decade. The initial water quality monitoring program is being conducted
by a CCMS student researcher and the students in the MAR 460 Field and Laboratory
Techniques in Marine Studies. The water quality monitoring at this location will
be continued this summer/fall by CCMS student researchers. Water quality parameters
examined in this study include temperature, salinity, dissolved oxygen, turbidity,
secchi disk depth, chlorophyll a, and pH. Water quality measurements are being measured
once per week at slack high tide.

Project DescriptionConnecticut is a coastal state with one of the most developed shorelines (% of shoreline
length) in the nation. Although Connecticut has a long maritime history, most Connecticut
residents do not feel a strong connection to the arm of the sea known as Long Island
Sound. This is, in part, because of lack of access. Most of the shoreline is private
or confined to use by citizens of particular municipalities. As a result, there is
a lack of awareness of and concern for the issues facing Long Island Sound. Hammonasset
State Beach is one of the places where the people of Connecticut can make positive
connections to the Sound and, in addition to being a source of recreation, is important
for that reason.

Beach and dune erosion has been an issue at Hammonasset since the 1920s, particularly
at the west end of the beach. Six storms in recent years (1989, 1991,1992, 1993,
1996, 2000, and 2011) have resulted in extensive boardwalk repair according to a study
conducted for the D.E.P. by Fuss and O’Neill and the Woods Hole Group. The report
notes that erosion is particularly intense along the west end of the park with erosion
rates averaging 1 foot per year between 1983 and 2007. The study indicates that erosion
has increased to as much as 2 feet per year during the last 33 years. Tropical Storm
Irene (2011) resulted in loss of the West Beach bathhouse and the west beach boardwalk.
Current thinking on the park of the D.E.E.P. and their consultants is that beach sand
is being carried to the east end of the 2-mile beach from the west end of the beach
by tidal currents. Based on preliminary studies, we believe this is incorrect and
that most of the eroded beach sand has been carried offshore and deposited in low,
broad underwater bars where it remains for long periods of time. We are testing this
hypothesis by surveying the topography of the beach and nearshore using the laser-based
surveying instrument. These measurements will be used to 1) confirm the existence
of the bars, 2) compute the total volume of the sand in the bars, and 3) recommend
to the state cost-efficient mitigation procedures for maintaining the west beach as
a viable resource, notably returning the sand to the beach via a slurry pump.

In addition to measuring beach and nearshore topography, grain size comparisons are
being made between the west beach sand and the sand in the bars and between the west
beach sand and the sand at the east beach. The topographic measurements will also
allow us to compute and compare slopes for the west and east beaches. Both grain
size and slope are related and both are measures of beach stability.

The relationship between grain size, loss-on-ignition, and metal concentrations are
being compared for several Connecticut harbors, including Norwalk, Bridgeport, and
New Haven to determine how the regression equations vary as a function of harbor.
It is expected that factors such as industrialization of the harbor and contamination
of the watershed, and levels of contamination in harbor sediments will affect the
numerical relationship between these factors. In harbors of similar contamination,
the regression equations should be similar. In harbors of dissimilar levels of contamination,
the y-intercept as well as the slope may vary.